Estimation of NOx Generation in A Commercial Pulverized Coal Burner using a Dynamic Chemical Reactor Network Model

Abstract

NOx generation in a coal burning furnace is estimating using a chemical reactor network model. The model is constructed with ideal chemical reactor modules, an input matrix and a tunable parameter matrix defining split ratios and flow rates among the ideal chemical reactor modules. Values in the tunable parameter matrix are learned by first measuring actual furnace outputs of the coal burning furnace for a known set of actual furnace inputs, and then applying the chemical reactor network, including an initially populated tunable parameter matrix, to a populated input matrix representing the known set of actual furnace inputs. The actual furnace outputs are compared with the output matrix, and the tunable parameter matrix is adjusted based on the comparison.

What is claimed is: 
     
         1 . A method for estimating NOx generation in a coal burning furnace, comprising:
 measuring actual furnace outputs of the coal burning furnace, including NOx generation, for a known set of actual furnace inputs;   constructing a chemical reactor network comprising:
 a plurality of ideal reactor modules; 
 an input matrix defining chemical reactor network inputs; and 
 a tunable parameter matrix defining split ratios and flow rates among the plurality of ideal reactor modules; 
   applying the chemical reactor network, including an initially populated tunable parameter matrix, to a populated input matrix representing the known set of actual furnace inputs, to create an output matrix including an estimate of NOx generation;   making a comparison of the actual furnace outputs with the output matrix;   based on the comparison, creating an adjusted tunable parameter matrix.   
     
     
         2 . The method of  claim 1 , wherein the chemical reactor network inputs include concentrations of compositions in coal. 
     
     
         3 . The method of  claim 1 , wherein the chemical reactor network inputs include input air temperature and flow rate. 
     
     
         4 . The method of  claim 1 , wherein the output matrix further includes volumetric flow rate and temperature. 
     
     
         5 . The method of  claim 1 , wherein the tunable parameter matrix further defines volumes of ideal reactor modules. 
     
     
         6 . The method of  claim 1 , wherein adjusting the tunable parameter matrix comprises grid searching for a best tunable parameter matrix. 
     
     
         7 . The method of  claim 6 , wherein the best tunable parameter matrix is a tunable parameter matrix yielding an output matrix having a smallest least squared error in comparison to the actual furnace outputs. 
     
     
         8 . The method of  claim 1 , wherein the method further comprises:
 repeating the operation of applying the chemical reactor network, using the adjusted tunable parameter matrix.   
     
     
         9 . The method of  claim 1 , wherein constructing a chemical reactor network is performed under an assumption that coal devolatilization depends only on coal composition and heating rate. 
     
     
         10 . The method of  claim 1 , wherein constructing a chemical reactor network is performed under assumptions that coal distributions are equal for a given set of gas burners, and that air is distributed equally among a given set of air ports. 
     
     
         11 . A system for estimating NOx generation in a coal burning furnace, comprising:
 a processor;   an interface connected to the processor and connected to receive measurements of actual furnace outputs of the coal burning furnace, including NOx generation, for a known set of actual furnace inputs;   computer readable media containing computer readable instructions that, when executed by the processor, cause the processor to perform the following operations:
 constructing a chemical reactor network comprising:
 a plurality of ideal reactor modules; 
 an input matrix defining chemical reactor network inputs; and 
 a tunable parameter matrix defining split ratios and flow rates among the plurality of ideal reactor modules; 
 
 applying the chemical reactor network, including an initially populated tunable parameter matrix, to a populated input matrix representing the known set of actual furnace inputs, to create an output matrix including an estimate of NOx generation; 
 making a comparison of the actual furnace outputs with the output matrix; 
 based on the comparison, creating an adjusted tunable parameter matrix. 
   
     
     
         12 . The system of  claim 11 , wherein the chemical reactor network inputs include concentrations of compositions in coal. 
     
     
         13 . The system of  claim 11 , wherein the chemical reactor network inputs include input air temperature and flow rate. 
     
     
         14 . The system of  claim 11 , wherein the output matrix further includes volumetric flow rate and temperature. 
     
     
         15 . The system of  claim 11 , wherein the tunable parameter matrix further defines volumes of ideal reactor modules. 
     
     
         16 . The system of  claim 11 , wherein adjusting the tunable parameter matrix comprises grid searching for a best tunable parameter matrix. 
     
     
         17 . The method of  claim 16 , wherein the best tunable parameter matrix is a tunable parameter matrix yielding an output matrix having a smallest least squared error in comparison to the actual furnace outputs. 
     
     
         18 . The system of  claim 11 , wherein the operations further comprise:
 repeating the operation of applying the chemical reactor network, using the adjusted tunable parameter matrix.   
     
     
         19 . The system of  claim 11 , wherein constructing a chemical reactor network is performed under an assumption that coal devolatilization depends only on coal composition and heating rate. 
     
     
         20 . The method of  claim 11 , wherein constructing a chemical reactor network is performed under assumptions that coal distributions are equal for a given set of gas burners, and that air is distributed equally among a given set of air ports.